Key Laboratory of Ministry of Education, Research Center of Chinese Herbal Resources and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China

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School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006, China

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Author to whom correspondence should be addressed.

Academic Editor: Marcello Iriti

Abstract Skimmianine is a furoquinoline alkaloid present mainly in the Rutaceae family. It has been reported to have analgesic, antispastic, sedative, anti-inflammatory, and other pharmacologic activities. Despite its critical pharmacological function, its metabolite profiling is still unclear. In this study, the in vivo metabolite profiling of skimmianine in rats was investigated using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry UPLC-Q-TOF-MS. The metabolites were predicted using MetabolitePilotTM software. These predicted metabolites were further analyzed by MS2 spectra, and compared with the detailed fragmentation pathway of the skimmianine standard and literature data. A total of 16 metabolites were identified for the first time in rat plasma, urine, and feces samples after oral administration of skimmianine. Skimmianine underwent extensive Phase I and Phase II metabolism in rats. The Phase I biotransformations of skimmianine consist of epoxidation of olefin on its furan ring M1 followed by the hydrolysis of the epoxide ring M4, hydroxylation M2, M3, O-demethylation M5-M7, didemethylation M14–M16. The Phase II biotransformations include glucuronide conjugation M8–M10 and sulfate conjugation M11–M13. The epoxidation of 2,3-olefinic bond followed by the hydrolysis of the epoxide ring and O-demethylation were the major metabolic pathways of skimmianine. The results provide key information for understanding the biotransformation processes of skimmianine and the related furoquinoline alkaloids. View Full-Text